Oracle11g drop ACL

If you have an already existing ACL, you will get errors like this:

ERROR at line 1:
ORA-31003: Parent /sys/acls/ already contains child entry resolve.xml
ORA-06512: at "SYS.DBMS_NETWORK_ACL_ADMIN", line 226
ORA-06512: at line 1

To drop the previous ACL, use  DROP_ACL command:

BEGIN
   DBMS_NETWORK_ACL_ADMIN.DROP_ACL(
      acl => 'resolve.xml');
END;